NEET-PG 2012 - Community Medicine Practice Questions

Q: School health checkup is primarily managed by which entity?

PHC. ***PHC (Primary Health Centre)*** - The **PHC is the primary entity responsible for managing school health checkups** in India as per the National Health Programs - The Medical Officer and health staff from the PHC conduct **periodic health examinations, immunizations, and screening programs** in schools within their jurisdiction - School health services are an integral component of the **MCH (Maternal and Child Health) services** provided by PHCs - The PHC maintains **health records of school children** and provides referral services for identified health problems *School health committee* - The School Health Committee plays a **coordinating and facilitating role** rather than primary management - It typically comprises school staff, parents, and local health representatives who help in **organizing logistics and follow-up** - While important for implementation, the committee does not conduct the actual medical examinations or manage the clinical aspects of health checkups *CHC* - The **Community Health Centre** serves as a referral center for PHCs and provides specialized services - Its role in school health is **secondary**, mainly providing referral services for cases requiring specialist consultation - CHCs do not directly conduct routine school health checkups *District hospital* - The **District Hospital** provides tertiary care and specialized medical services - Its involvement in school health is limited to **referral cases requiring advanced diagnostics or treatment** - It does not participate in routine primary management of school health checkup programs

Q: Which of the following best describes the concept where a suspected cause precedes the observed effect?

Temporal association. ***Temporal association*** - This principle in **causal inference** emphasizes that for a factor to be a cause, it must precede the effect. - In epidemiology, it's crucial to establish that exposure occurred **before the disease manifestation**. *Consistency of association* - Refers to the observation of a **similar association across different studies** and populations. - While important for causal inference, it does not directly address the timing of cause and effect. *Strength of association* - Quantifies how often the **exposure and outcome co-occur**, often measured by relative risk or odds ratio. - A strong association is more likely to be causal, but it doesn't confirm that the cause came before the effect. *Coherence of association* - Implies that the observed association should be **consistent with existing biological and medical knowledge**. - This criterion supports the plausibility of an association but doesn't specifically deal with the temporal sequence.

Q: Following are examples of human "dead end" diseases except -

Bubonic plague. ***Bubonic plague (Plague)*** - The question refers to **plague in general**, which includes multiple clinical forms. - While **bubonic plague** (the most common form) is transmitted via **flea bites** from infected rodents and humans are typically dead-end hosts for this form, **pneumonic plague** (secondary complication or primary infection) allows **human-to-human transmission** via respiratory droplets. - This makes plague the **exception** among the listed diseases, as humans can serve as a source of infection to others in the pneumonic form, unlike true dead-end host situations. *Japanese encephalitis* - Humans are **dead-end hosts** for Japanese encephalitis virus. - Infected humans do not develop sufficient **viremia** to infect feeding mosquitoes. - The virus maintains its cycle between **Culex mosquitoes**, **pigs** (amplifying hosts), and **wading birds**, with humans being incidental hosts. *Hydatid disease* - Humans are **definitive dead-end hosts** for *Echinococcus granulosus* (causing cystic echinococcosis/hydatid disease). - The normal life cycle requires **definitive hosts** (dogs, canids) and **intermediate hosts** (sheep, cattle). - Humans develop **hydatid cysts** but cannot transmit the infection further as the parasite cannot complete its life cycle in humans. *Leishmaniasis* - In most forms of leishmaniasis, humans are considered **dead-end or accidental hosts**, particularly in **zoonotic cutaneous leishmaniasis** where animal reservoirs (rodents, dogs) maintain transmission. - However, in **anthroponotic visceral leishmaniasis** (*Leishmania donovani* in the Indian subcontinent), humans can serve as reservoir hosts. - For the purpose of this question, leishmaniasis is generally classified with dead-end diseases as the majority of leishmaniasis forms have zoonotic cycles where humans are incidental hosts with limited onward transmission.

Q: Which disease is associated with a propagative cycle?

Filaria. ***Filaria*** - The **filarial worm** undergoes a **biological transmission cycle** in the mosquito vector where microfilariae develop through larval stages (L1 → L2 → L3) with multiplication. - This represents a **cyclopropagative cycle** (both development and multiplication occur in the vector). - In the context of this question and classical teaching, filaria is considered the standard example of biological transmission with vector multiplication. - The infective L3 larvae multiply from a single microfilaria, and multiple larvae can develop within one mosquito. *Plague* - **Plague** (*Yersinia pestis*) is transmitted by fleas through **mechanical transmission**. - Bacteria multiply in the flea's gut causing blockage (blocking transmission), but this is not considered a true biological cycle. - The pathogen does not undergo developmental stages in the vector. *Malaria* - **Malaria** (*Plasmodium* spp.) undergoes the **sporogonic cycle** in the mosquito, which is also a **cyclopropagative cycle**. - Gametocytes → ookinete → oocyst → sporozoites (development with multiplication). - While biologically similar to filaria, in classical epidemiology teaching, filaria is more commonly cited as the example for propagative transmission. *None of the options* - This option is incorrect as filaria demonstrates biological transmission with multiplication in the vector. - Both filaria and malaria technically undergo cyclopropagative cycles, but filaria is the conventional answer in medical education contexts.

Q: The primary reservoir for leptospirosis transmission is:

Rat. ***Correct Answer: Rat*** - **Rats** (and other rodents) are considered the primary natural reservoir for *Leptospira* bacteria worldwide and are **asymptomatic carriers**. - They excrete the bacteria in their urine, contaminating water and soil, which serves as the main source of human infection. *Incorrect: Cat* - While cats can become infected with *Leptospira*, they are **not typically considered significant reservoirs** for human transmission. - Their role in the epidemiologic cycle of leptospirosis is generally minor compared to rodents and some other mammals. *Incorrect: Dog* - **Dogs** can contract leptospirosis and excrete the bacteria in their urine, posing a risk to humans, but they are generally considered **incidental hosts or secondary reservoirs**, not the primary one. - Vaccination in dogs helps reduce their role in transmission. *Incorrect: Fish* - **Fish are not known to be reservoirs** for *Leptospira* bacteria. - Leptospirosis is primarily transmitted through contact with infected animal urine, not aquatic life like fish.

Q: Schistosomiasis is an example of which type of zoonosis that requires an intermediate host?

Meta-zoonoses. ***Meta-zoonoses*** - **Meta-zoonoses** are defined as zoonotic diseases that require an **intermediate invertebrate host** for the completion of the parasite's life cycle. - **Schistosomiasis** fits this definition as it involves fresh water snails acting as an intermediate host, where the parasite undergoes essential developmental stages. *Cyclo-zoonoses* - **Cyclo-zoonoses** require **more than one vertebrate host species** but no invertebrate host for the completion of the infectious agent's life cycle. - An example would be **Taeniasis**, which involves humans and cattle or pigs, but not an invertebrate. *Direct-zoonoses* - **Direct-zoonoses** are transmitted directly from an **infected vertebrate host to a susceptible vertebrate host** without the need for an intermediate host or vector. - Examples include **rabies** or **brucellosis**, which are passed directly from animals to humans. *Sporo-zoonoses* - **Sporo-zoonoses** are zoonoses where the infectious agent undergoes **sporogonic development in an invertebrate host**, but this term is not a standard or widely recognized category in the same way as direct, cyclo-, or meta-zoonoses. - The more appropriate term for diseases involving an invertebrate intermediate host is **meta-zoonoses**.

Q: Which graphical representation is best suited for depicting continuous quantitative data?

Histogram. **Histogram** - A **histogram** is specifically designed for depicting the distribution of **continuous quantitative data** by dividing the data into bins and showing the frequency of data points within each bin. - The bars in a histogram are adjacent, indicating the continuous nature of the data and representing ranges of values. *Bar diagram* - A **bar diagram** (or bar chart) is typically used for comparing **discrete categories** or displaying changes over time for categorical data. - The bars in a bar diagram are usually separated, emphasizing distinct categories rather than continuous ranges. *Pie chart* - A **pie chart** is used to show the **proportions of a whole**, representing parts of a composition for categorical data. - It is not suitable for continuous data as it provides no information about the distribution or frequency across a range of values. *Pictogram* - A **pictogram** uses images or icons to represent data, making it visually engaging, but it is generally used for **simple comparisons of discrete or categorical data**. - It lacks the precision and detail required to accurately depict the distribution or frequency of continuous quantitative data.

Q: Berksonian bias is a type of ?

Selection bias. ***Selection bias*** - **Berkson's bias** is a form of **selection bias** that arises in studies conducted using hospital data. - It occurs when the probability of admission to a hospital or inclusion in a study is conditional on both exposure and disease status, leading to a **flawed association** between them. *Interviewer bias* - **Interviewer bias** is a type of **information bias** where the interviewer's expectations or knowledge about the study or participants influence the way information is sought or recorded. - This typically affects the **data collection process** and not the selection of participants. *Information bias* - **Information bias** is a broad category of biases that arise from **systematic errors in measurement** or classification of exposure or disease. - While Berkson's bias can lead to misinformation, its root cause is in how subjects are selected, not how data on those subjects is collected after selection. *Recall bias* - **Recall bias** is a type of **information bias** where there are systematic differences in the way participants **recall past events or exposures**. - It is particularly common in **case-control studies** where individuals with a disease may remember exposures differently than healthy controls.

Q: What is the term for the time between infection and maximum infectivity?

Generation time. ***Generation time*** - This is the **time interval** between receipt of infection by a host and the moment of **maximum infectivity** of that same host. - It is a crucial parameter in epidemiology for understanding **disease transmission dynamics** and the speed at which an epidemic can spread. *Incubation period* - This refers to the time from **exposure to an infectious agent** until the **onset of symptoms**. - It does not directly account for the timing of viral shedding or peak infectivity. *Serial interval* - This is the time between **symptom onset in a primary case** and **symptom onset in a secondary case** it infects. - While related to transmission, it focuses on symptomatic presentation rather than peak infectivity. *Communicable period* - This is the time during which an infected individual is **capable of transmitting** the infectious agent to others. - It represents the entire duration of potential transmission, not specifically the peak infectivity.

Question 1

School health checkup is primarily managed by which entity?

Accepted Answer

PHC

Answer

CHC

Answer

District hospital

Answer

School health committee

Question 2

Which statement best describes the concept of web of causation in disease?

Accepted Answer

Considers all relevant factors associated with disease causation.

Answer

Applicable primarily to common diseases.

Answer

Focuses on epidemiological ratios.

Answer

Aids in interrupting the transmission of diseases.

Question 3

Which of the following best describes the concept where a suspected cause precedes the observed effect?

Accepted Answer

Temporal association

Answer

Consistency of association

Answer

Strength of association

Answer

Coherence of association

Question 4

Following are examples of human "dead end" diseases except -

Accepted Answer

Bubonic plague

Answer

Hydatid disease

Answer

Japanese encephalitis

Answer

Leishmaniasis

Question 5

Which disease is associated with a propagative cycle?

Accepted Answer

Filaria

Answer

None of the options

Answer

Plague

Answer

Malaria

Question 6

The primary reservoir for leptospirosis transmission is:

Accepted Answer

Rat

Answer

Cat

Answer

Dog

Answer

Fish

Question 7

Schistosomiasis is an example of which type of zoonosis that requires an intermediate host?

Accepted Answer

Meta-zoonoses

Answer

Cyclo-zoonoses

Answer

Direct-zoonoses

Answer

Sporo-zoonoses

Question 8

Which graphical representation is best suited for depicting continuous quantitative data?

Accepted Answer

Histogram

Answer

Bar diagram

Answer

Pie chart

Answer

Pictogram

Question 9

Berksonian bias is a type of ?

Accepted Answer

Selection bias

Answer

Information bias

Answer

Interviewer bias

Answer

Recall bias

Question 10

What is the term for the time between infection and maximum infectivity?

Accepted Answer

Generation time

Answer

Communicable period

Answer

Incubation period

Answer

Serial interval

NEET-PG 2012 — Community Medicine